Field of the Invention.
This invention relates to a glue nozzle and particularly to nondrip nozzles and glue systems for use in applying glue onto surfaces of material such as paper, cardboard, film, wood or any other material requiring gluing.
Description of the Prior Art.
There are three basic methods of applying glue to the surface of material, which material is moving relatively to the glue applicator: a spraying method whereby the glue is sprayed from a nozzle located adjacent the surface; a method akin to printing, wherein the glue is "printed" onto the surface by means of a rotating wheel having recesses therein adapted to be filled with glue; and pressurized glue systems, wherein a glue nozzle touches the surface upon which glue is to be applied. One of the most perplexing problems associated with these known methods of applying glue is leakage from the glue applicator during the periods in which it is not desired to apply glue to a surface, i.e., at the end of application, shut-down of the glue applicator, etc. Another serious problem associated with pressurized gluing systems is plugging of the small glue nozzle orifices with contaminents; for example, hot melt glues undergo degradation with continual heating, causing hardened bits of glue which eventually clog the small orifices and stop the flow of glue.